What is CVE-2025-66737?

CVE-2025-66737 is a medium-severity vulnerability in Yealink Sip-T21\(p\)e2, classified under Relative Path Traversal. CVSS score: 4.3/10. Published 2025-12-26.

How severe is CVE-2025-66737?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Path Traversal in Yealink Sip-T21\(p\)e2

CVE-2025-66737

Yealink T21P_E2 Phone 52.84.0.15 is vulnerable to Directory Traversal. A remote normal privileged attacker can read arbitrary files via a crafted request result read function of the diagnostic component.

Published 2025-12-26 · last modified 2026-07-05.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.007 (49.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: -0.000

Affected products

Yealink Sip-T21\(p\)e2
Yealink Sip-T21\(p\)e2 Firmware — versions 52.84.0.15

Weakness classification (CWE)

CWE-23 — Relative Path Traversal

References

yealink.com (Product)
drive.google.com/file/d/1MpxnCL4koKupqWWDmY3ljlybjIPD8ieD/view (Exploit)

Frequently asked questions

What is CVE-2025-66737?: CVE-2025-66737 is a medium-severity vulnerability in Yealink Sip-T21\(p\)e2, classified under Relative Path Traversal. CVSS score: 4.3/10. Published 2025-12-26.
How severe is CVE-2025-66737?: Medium severity. CVSS v3 base score is 4.3 out of 10.